Portable light bulb



FIG. 1 is a top view of a portable light bulb showing my new design.

FIG. 2 is a bottom view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a back view thereof;

FIG. 5 is a side view thereof;

FIG. 6 is the other side view thereof; and,

FIG. 7 is a perspective view thereof.

The broken lines in FIGS. 1–7 are for illustrative purposes and form no part of the claimed design. 

The ornamental design for a portable light bulb, as shown and described. 